1 files changed, 87 insertions, 0 deletions
diff --git a/Crypto/src/cms/KeyTransRecipientInfoGenerator.cs b/Crypto/src/cms/KeyTransRecipientInfoGenerator.cs
new file mode 100644
index 000000000..0992e6da6
--- /dev/null
+++ b/Crypto/src/cms/KeyTransRecipientInfoGenerator.cs
@@ -0,0 +1,87 @@
+using System;
+using System.IO;
+
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.Cms;
+using Org.BouncyCastle.Asn1.X509;
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Security;
+using Org.BouncyCastle.X509;
+
+namespace Org.BouncyCastle.Cms
+{
+ internal class KeyTransRecipientInfoGenerator : RecipientInfoGenerator
+ {
+ private static readonly CmsEnvelopedHelper Helper = CmsEnvelopedHelper.Instance;
+
+ private TbsCertificateStructure recipientTbsCert;
+ private AsymmetricKeyParameter recipientPublicKey;
+ private Asn1OctetString subjectKeyIdentifier;
+
+ // Derived fields
+ private SubjectPublicKeyInfo info;
+
+ internal KeyTransRecipientInfoGenerator()
+ {
+ }
+
+ internal X509Certificate RecipientCert
+ {
+ set
+ {
+ this.recipientTbsCert = CmsUtilities.GetTbsCertificateStructure(value);
+ this.recipientPublicKey = value.GetPublicKey();
+ this.info = recipientTbsCert.SubjectPublicKeyInfo;
+ }
+ }
+
+ internal AsymmetricKeyParameter RecipientPublicKey
+ {
+ set
+ {
+ this.recipientPublicKey = value;
+
+ try
+ {
+ info = SubjectPublicKeyInfoFactory.CreateSubjectPublicKeyInfo(
+ recipientPublicKey);
+ }
+ catch (IOException)
+ {
+ throw new ArgumentException("can't extract key algorithm from this key");
+ }
+ }
+ }
+
+ internal Asn1OctetString SubjectKeyIdentifier
+ {
+ set { this.subjectKeyIdentifier = value; }
+ }
+
+ public RecipientInfo Generate(KeyParameter contentEncryptionKey, SecureRandom random)
+ {
+ byte[] keyBytes = contentEncryptionKey.GetKey();
+ AlgorithmIdentifier keyEncryptionAlgorithm = info.AlgorithmID;
+
+ IWrapper keyWrapper = Helper.CreateWrapper(keyEncryptionAlgorithm.ObjectID.Id);
+ keyWrapper.Init(true, new ParametersWithRandom(recipientPublicKey, random));
+ byte[] encryptedKeyBytes = keyWrapper.Wrap(keyBytes, 0, keyBytes.Length);
+
+ RecipientIdentifier recipId;
+ if (recipientTbsCert != null)
+ {
+ IssuerAndSerialNumber issuerAndSerial = new IssuerAndSerialNumber(
+ recipientTbsCert.Issuer, recipientTbsCert.SerialNumber.Value);
+ recipId = new RecipientIdentifier(issuerAndSerial);
+ }
+ else
+ {
+ recipId = new RecipientIdentifier(subjectKeyIdentifier);
+ }
+
+ return new RecipientInfo(new KeyTransRecipientInfo(recipId, keyEncryptionAlgorithm,
+ new DerOctetString(encryptedKeyBytes)));
+ }
+ }
+}
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